How We Calculate The Zipper Length (Formula Included)

The rules of zipper measurement is very simple but some time it becomes a matter of big trouble for us. Actually it depends on the fabric & zipper properties. So, at first we must need an idea about the shrinkage of body fabric & zipper tape. Some zipper measurements are not very complicated such as pocket, leg opening etc. Here, we only discuss about the front long zipper of sweat shirt or Jacket or as like that.

A) If the garments is hooded sweat shirt and the zipper goes up to front neck drop from bottom then the rules will as under -

Say,
Body length (From HPS) – 73 cm
Front Neck drop (CB) – 8 cm
Back Neck drop – 2 cm
(Use the below rule if the body length measure from HPS)
Rules  : Body length - (Front neck drop + Back neck drop) – 2% to 3%
= ( 73 – (8 + 2)) -2%
= ( 73 – 10 ) – 2%
=  63 – 2%
=  61.5 cm
OR
Body length (From CB) – 71 cm
Front Neck drop(CB) – 8 cm
(Use the below rule if the body length measure from CB)
Rules : (Body length - Front neck drop ) – 2% to 3%
= ( 71 – 8 ) -2%
= ( 71 – 8 ) – 2%
=  63 – 2%
=  61.5 cm
B) If the garments is high neck and the zipper goes up to to of high neck drop from bottom then the rules will as under -

Say,
Body length (From CB) – 65 cm
Front Neck drop – 6 cm
Height of high neck – 6 cm
Rules : (Body length - Front neck drop) – 2% to 3% + Height of high neck
= ( 65 – 6) -2% + 6
= ( 59 ) – 2% + 6
=  57.82 + 6
=  63.82 cm  = 64 cm
Moreover, the rules is not always remain fixed, its may vary depends on practical situations.
However, I always advise that you must confirm the zipper measurement with your cutting master & production manager before place an order.